This application claims the priority of German patent document 100 20 087.7, filed Apr. 22, 2000, the disclosure of which is expressly incorporated by reference herein.
The present invention relates to a compact fuel cell system.
The fuel used in conventional fuel cells is hydrogen, which is produced from a liquid fuel, for example from methanol, in stages connected upstream of the fuel cell. Since the production of hydrogen usually also involves the formation of carbon monoxide, which is damaging to the fuel cell, a gas cleaning unit is additionally incorporated, so that the anode side of the fuel cell is exposed to substantially pure hydrogen. If a liquid fuel is used as the starting material, an evaporator unit is often also provided. Finally, to avoid environmental pollution, an exhaust-gas treatment unit is provided, in which all the combustible constituents of the fuel cell exhaust gases are converted as completely as possible. To construct an overall system which is able to function, all these components have to be connected to one another, both mechanically, and in terms of flow.
It is an object of the invention to provide a compact fuel cell system which is suitable for mechanical installation.
This and other objects and advantages are achieved by the fuel cell system according to the invention, having a single-stage or multistage gas generation unit for producing a hydrogen-rich gas from an untreated fuel, having a single-stage or multistage gas cleaning unit, at least one fuel cell and a single-stage or multistage exhaust-gas treatment unit for converting the fuel cell exhaust gases as completely as possible. At least two sub-units of the fuel cell system are connected to one another mechanically and in terms of flow by means of a connecting plate.
A considerable advantage of this arrangement is that, compared to conventional, sometimes highly complex arrangements of pipes, this arrangement is very compact and clear. There is no longer any risk of connecting lines being incorrectly connected. A further significant advantage is that this structure is suitable for mechanical installation and can therefore advantageously be used for automated production in relatively large numbers.
Furthermore, it is easy to exchange or replace individual sub-units, for example in the event of a defect. A final advantage is that the control technology as well as measurement and metering points can be integrated.
A further problem of fuel cell systems is that individual sub-units operate at highly divergent temperatures. In the fuel cell system according to the invention, it is easy to thermally isolate the sub-units by selecting a suitable material for the connecting plate 10. If, in the first exemplary embodiment, the connecting plate is of very rigid design, it is also possible to reduce problems caused by vibrations.
Other objects, advantages and novel features of the present invention will become apparent from the following detailed description of the invention when considered in conjunction with the accompanying drawings.